26 research outputs found
Differential sensitivity to pro-oxidant exposure in two populations of killifish (Fundulus heteroclitus)
New Bedford Harbor (MA, U.S.A.; NBH) is a Superfund site inhabited by Atlantic killifish (Fundulus heteroclitus) with altered aryl hydrocarbon receptor (Ahr) signaling, leading to resistance to effects of polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The Ahr is a transcription factor that regulates gene expression of many Phase I and II detoxifying enzymes and interacts with Nrf2, a transcription factor that regulates the response to oxidative stress. This study tested the hypothesis that PCB-resistant killifish exhibit altered sensitivity to oxidative stress. Killifish F(1) embryos from NBH and a clean reference site (Scorton Creek, MA, U.S.A.; SC) were exposed to model pro-oxidant and Nrf2-activator, tert-butylhydroquinone (tBHQ). Embryos were exposed at specific embryonic developmental stages (5, 7, and 9 days post fertilization) and toxicity was assessed, using a deformity score, survival, heart rate, and gene expression to compare sensitivity between PCB-resistant and PCB-sensitive (reference) populations. Acute exposure to tBHQ resulted in transient reduction in heart rate in NBH and SC F(1) embryos. However, embryos from NBH were more sensitive to tBHQ, with more frequent and severe deformities, including pericardial edema, tail deformities, small body size, and reduced pigment and erythrocytes. NBH embryos had lower basal expression of antioxidant genes catalase and glutathione-S-transferase alpha (gsta), and upon exposure to tBHQ, exhibited lower levels of expression of catalase, gsta, and superoxide dismutase compared to controls. This result suggests that adaptation to tolerate PCBs has altered the sensitivity of NBH fish to oxidative stress during embryonic development, demonstrating a cost of the PCB resistance adaptation
Embryo Microinjection of Selenomethionine Reduces Hatchability and Modifies Oxidant Responsive Gene Expression in Zebrafish
The role of CYP1A inhibition in the embryotoxic interactions between hypoxia and polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures in zebrafish (Danio rerio)
Biological effect monitoring in dab (Limanda limanda) using gene transcript of CYP1A1 or ERODâa comparison
Developmental Expression of the Nfe2-Related Factor (Nrf) Transcription Factor Family in the Zebrafish, Danio rerio
Acute toxicity of polybrominated diphenyl ethers (PBDEs) for turbot (Psetta maxima) early life stages (ELS)
Background, aim and scope The environmental presence of
polybrominated diphenyl ethers (PBDEs), among which
BDE-47 and BDE-99 are particularly abundant, makes
toxicity data necessary to assess the hazard risk posed by
PBDE to aquatic organisms. This study examines the
effects of BDE-47 and BDE-99 on embryo-larval stages
of the marine flatfish turbot.
Materials and methods The turbot embryos were exposed
at nominal concentrations of BDE-47 and BDE-99 for
6 days. Selected dose levels were relevant for investigating
sublethal and lethal effects.
Results Both tested compounds caused lethal toxicity as
well as non-lethal malformations during embryo development.
We found a high toxic potency of BDE-47 compared
to BDE-99 (LC50 values for embryos and larvae, respectively,
BDE-47: 27.35 and 14.13 ÎŒg Lâ1; BDE-99: 38.28
and 29.64 ÎŒg Lâ1).
Discussion The present study shows high sensitivity of fish
early life stages (ELS) to PBDE compounds. Based on
environmental concentrations of dissolved PBDEs from various aquatic ecosystems, waterborne BDE-47 and BDE-
99 pose little risk of acute toxicity to marine fish at relevant
environmental concentrations.
Conclusions Turbot fish ELS proved to be an excellent
model for the study of ecotoxicity of contaminants in
seawater. The results demonstrate harmful effects of PBDE
on turbot ELS at concentrations in the range of parts per
billion units.
Recommendations and perspectives In the perspective of
risk assessment, ELS endpoints provide rapid, costeffective
and ecologically relevant information, and links
should be sought between these short-term tests and effects
of long-term exposures in more realistic scenarios.MAE-PCI CTM2009-10908VersiĂłn del editor2,651